Coal jig



Feb. 5, 1929. 1,701,155

M. s. HAcHlTA COAL JIG mea nay 14. 1925 2 sums-snm 1 Je J3 lffff/M Ill'w.E @s 143 E M I:

x hdl 2 .if

INVENTOR.

1,701,155 M. s. HAcHlTA Feb. 5, 1929.

COAL JIG Filed lay 14, 1925 2 Sheets-Shl 2 I N VBV TOR.

Y ATTORNEY.

- pure coal, coal of low grade or middlings Patented Feb. 5, 1929. E

UNITED STATES 1,701,155 PATENTN oFFEE1cE.

MAXIMILIAN s HACHITA, or wILxEs-Baann, r11Nirsurtvaiiiii.`

COAL J IG.

Application tiled` May 14, 1925. Serial No. 30,161.

rl"his invention relates to apparatus employed in the cleaning of coalof the type generally known in the art as coal jigs;

The general object of the invention is to provide an improved and novelconstruction ot coal jig by the employment of' which coal may be morethoroughly and efficiently separated from impurities consisting ofearthy matter, such as rock, stone, slate, pebbles, sand,` pyrite, etc.,than heretofore has been practical.

It is also an obj ect of the invention to provide an improved and novelconstruction of coal j igging apparatus whereby a mixture of7 as it iscalled7 and earthy material, such as rock, stone, etc., may be separatedinto its three constituents or separate parts.

Other objects of the invention are,to provide an apparatus of novelconstruction such that the thickness of the bed of material upon the jigor separating pan is maintained' at a minimuim' so that the pulsatingwater operating thereon may have a maximum effect in bringing aboutseparation; to provide an apparatus of novel construction such that thebed of material upon the bottom of the jig or separating an shall beallowed to expand freely, there y producing a porous bed such that theseparate particles or elements thereof may be subjected to approximatelyequal forces produced by the pulsating action of' the water; to provideanovel construction of jig pan comprising troughs extendinglongitudinally thereof, along which the heavier portions of material arecaused to travel or flow, with which troughs are associated meanswhereby the effect of the pulsations of water in one trough isindependent of the effect of' the pulsations in other troughs to providemeans extending transversely of the said troughs for causing lateralmovement transversely of the said troughs of the lighter portion of thematerial being treated, for instance, pure coal; to rovide novel meanswhereby the portion o the material which does not require jigging orcleansing is discharged in the early part of the jigging operation, sothat the portion of the material being treated which reaches the main igarea oi the jig pan contains all ofthe heavier material and a relativelysmall proportion of pure coal from which it is to be separated; and alsoto provide novel means whereby the mixture of material being treated maybe separated into three different portions.

`my invention;

I shall not undertake atthis point to indicate further objects andadvantages incident to my invention, but suchl other objects andadvantages will be referred to inthe detailed description `of the saidinvention which follows or will be apparent from such description.

trated one form of mechanical embodiment oft-he invention.` j j 1t is tobe understood, however, that the invention is susceptible of embodimentin other forms of construction than that shown and that changes in thedetails of constructioii may be made within the scopeof the claimswithout departing from the invention.

In the drawings:

Fig. 1 is a view in vertical longitudinalv j section of a coal jigapparatus embodying F 2 is a. top plan view of the same;

Fig. is a transverse vertical sectional view taken on the line 3-3 ofFig. 1; 1 1 Fig. 4 is a top plan view of the vibratory .jig pan of theapparatus; j

Fig. 5 is a` view in side elevation of the/ji g pan structure, with a`portion broken away to show a part thereof in section;

Fig; 6 is a view in transverse section of the jig pan structure;

Fig. 7 is a rear end elevation ofthe jig pan; and v Fig. 8 is asectional view of the bottom of.

the j inf pan taken on the line 8-8 of Fig. 4.

Re erring to the drawings:

1 designates a tank adapted Vto contain water employed in the washingand cleansing of the coal, which tank is supported by a frame structure2 in known manner. tion of the front wall. and the rear wall converge asindicated in Fig. 1 to an opening 3 which is adapted to be opened andclosed by a valve 4 which may be operated by a lever 5.

The j igpan structure designated as awholc` at 10 is suspended uponvertical bars 11 and 11a from eccentric straps `12 mounted uponeccentrics 13 which in turn are supported upon a revoluble shaft 14,upon one end o"I` which fast and Vloose wheels 15 are provided for" thepurpose of' controlling the operation of the said sha-ft. i

The vertical bars 11 and 11a are secured by riveting to the oppositesides 16 and 17 of the jig pan.` The lower end of the bar 1l extendsthrough an opening in the horizontal portion or flange of a bracket 18adjustably secured to the adjacent side wall of the tanlr 1 by means ofbolts 19. The upper ends of the bars 11 and 11' project into holes inthe lower ends of projecting portions of the eccentric straps 12 and aresecured therein by means of bolts 20. The upper ends of the said bars 11and 1ln are provided with a plurality ofholes or f openingstherethrough, so that either of the saidbars may be adjustedverticallyuso as to wary thelength thereof,

andfithereby vary thellateral or `transverse 15 pitch or inclination ofthe bottom 21 of the jig pan. The pitch or inclination of the bottom21of the jigpanin a longitudinaldirection may lie-varied by adjusting thebracket 1.8 `in one direction or the other.

The bottom ofthe jig pan is provided with perforations as is usual insuch structures.

i Forithe purpose of effecting separation of thepure coal from therelatively heavy material of the character already indicated the 25 jigpan is provided with a series of longitudinally extending plates or bars25 and with `atseriesof transversely..extending plates or bars 26 whichradiate from a common distant center. The longitudinally extendingbars30 `or plates 25 are mounted directlyupon Vthebottom 21 of the jig panand are spaced from each other, as shownso as to provide a series oftroughs or runways. The bars 25 are relatively narrow, beingapproximately one and one-halftinches (1l/2) in width, while the bars 26are approximately three inches (37) in width. i The latter bars arelocated above the bars 25 and are provided with notches 27, as shown,which notches are of rightangle 4o triangular shape. The `bars 25project into the notches and lit againstthe vertical walls `or shouldersthereof, as best shown in Fig. G

of the drawings.

As already described, the pan is sup ported so that its bottom has botha longitudinal and a transverse pitch or inclination, sinconsequence ofwhich the upper left hand `corner of said bottom (referring to Fig. l ofthe drawings) is the highest point of the same. The feed chute 30 islocated in this .corner of the jig' pan,iso that the mixture to betreated is Idelivered to the highest point or portion of the bottomthereof. Theoppositefends of the three plates or bars Q6 located`nearest to theffeed chute 30 are connected to the side 16 and the lefthand end wall of the jigipan. Assuming that the longitudinal andtransverse inclinations of the bottom of the pan, previously referredto, are equal, andthat the opposite `ends of `the plates or bars 2G arelocated at points substantially equidistant from the upper eft handcorner of the bottom of the jig pan it will be apparentthat `theopposite ends of each plate or bar are located substantially the samevertical distance from any assumed lower horizontal plane, so that thetop edge of each of the said plates or bars occupies a horizontal-plane.lt will be apparent, however, that the upper edges of these plates orbars will occupy different levels. By reason of thisarrangement in whichthe lirst three of the plates or bars 26 referred to occupysubstantially horizontal planes it will be apparent that the mixturedelivered from the feed chute 30 is evenly distributed over the portionof the bottom of the pan included between the third plate 2G and thefeed chute.

Upon reference to Fig. el it will be noted that if the plates or `bars26 were extended upwardly they would ultimately meet at a point upon anextension of the plate or bar constituting the right hand end of the panshown in plan in said ligure. la a result of that arrangement it will beapparent that the relation of the bars 26 to the length of the jig panor to the bars 25 varies as they approach the right hand end of the jigpan. It will be noted that the bars Q6 near the right hand end of thejig pan extend downwardly very nearly at right angles to the bars 25 0ralmost vertically, whereas the bars 26 atthe opposite end of the jigpanextend diagonally across the said jig pan with the consequence that thebar 30 and the first two bars Q6 operate to effect equal distribution ofthe material to be washed upon the `jig pan thereafter as the materialapproaches the opposite end of the jig pan the bars 26 tend to causedownward movement of Athe cleaned or washed portion of the material toeffect discharge of the same over the edge of the side 17.

fllheimixture `of coal, iniddlings or low grade coal, and earthlymaterial, such as stone, slate, etc., is delivered to the `iig panthrough the feed chute 30, which in the construction sliown istriangular in cross section. Any suitable meansl may be employed forcontrolling the` rate of feed ofthe mixture from the feed` chute intothe pan. The material from the chute is delivered into the jig paninfront of or above the first of the transversely .extending bars orplates 2G. As already stated, the upper edge of each of the first threeof these bars 0r plates occupies a substantially horiontal plane, thesaid planes occupying` different levels. As a result of this arrangementthe mixture being treated is spread uniformly over the first or initialpart ofthe. jig pan bottoni.

The end and side walls ofthe jig pan are extended i below the bottom 21thereof, as shown at 35, and the lower edges of said walls are beveledoutwardly as indicated at 3G. Extending downwardly from the bottom 21are aV of plates 3T which are in the same vertical planes as thelongitudinally exteiuling bars or pla-tes and constitute dis tributorbailles.

ln the operation of the apparatus the llt) lil

Sii

a pan as the latter moves downwardly.

pan, by reason of being supported upon the eccentrics 13, `will becaused to vibrate in known manner. `When `the jig pan isvibrated thewater in the tank flows upwardly through the perforations in the bottom2l thereof as it descends. The upward flow occurs, therefore, atintervals. The depending Walls 35, the inner bottom edges of which arebeveled outwardly, as indicated at 36, operate upon a downward movementof the pau to couline the water in the tank within the space surroundedby said walls and tend to cause. the saine to flow upwardly through theperforations in thebottom 21 of the jig In other words, these wallspreventthe lateral spreading of the water which is located directlyunderneath the bottom ofthe jig pan when the. latter is moveddownwardly. The presence of the spaced plates underneath the bottom 2lof the jig pan operatesto render the pulsations of the water through theportions of the jig pan between adjacent bars or plates 25 independentof each other. In other words, the material in one of said troughs, ineffect, is treated independently of that in the other troughs. i

It will be notedthat the end walls and the side walljl' of the jig panextend a considerable distance above the bottom 2l thereof` while theportion of the wall l? of thesaid pan above the bottom 21 is of a heightsubstantially the saine as that of the bar or plate Q5 adjacent thereto.As a result of this arrangement, it will be seen that the water whichfiows upwardly `th1`"ough the perforations in the bottom 21 is caused toflow laterally or transversely of the bars or plates 25 in the directionof the length of the transverse bars orplates 26, and also in thedirection of the transverse inclination or pitch of the bottom 21. Itmay be noted that in practice the depending portions of the side and endwalls of the jig pan are referred to as a four-wall baffle, while theupwardly projecting portions of the end walls and the side wall 16 arereferred to as a three-wall baffle. In actual practice it has been foundthat apparently there is no reflex action of the water upon an upwardmovement of the jig pan, the reason being that the water flows in thedirection of least resistance which, in the cimstruction shown, istransversely of the hars or plates 25 and in the direction of the lengthofthe bars or plates 26 which is. the direction along which the purecoal flows.

It has been found inpractice that the heaviest portions of the refusematerial, such as rock, stone. slate, pebbles, sand, pyrite, etc., arecaught by the first two or three of the longitudinal hars or plates 25,while the middlings material which has some fuel value is caught by theremaining lower plates 25. The material in the g pan being treated hasfree movement so that the respective part-iing lighter than the earthymaterial and the middlings7 portion ofthe mixture moves or flowslaterally so that due to the inclination of the bottom of the jig panand to the transverse flow of the water produced by the threewall bafflea large proportion thereof is discharged from between the third andfourth and fourth and fifth of the transversely extendingI bars orplates 26. It will be understood that during theoperation of the devicethe coal being the lighter portion of the mixture assumes a positionabove the heavier portion of the material and is discharged laterallyfromvthe jig pan over the upper edge of the side wall 17. As al resultof the discharge of the greater proportion of' the pure coal j frombetween the third and fourth and fourth and fifth of the transverselyextending bars or plates a mixture including a relatively smallproportion of pure coal is left for treatment in the main jiggingportion of the jigging structure. i

As the treatment continues the coalwhich is the lighter is caused tomove laterally toward the side `wall 1T by the transverse bars or plates26 and is ultimately discharged over the upper edge of said side wall,while the heavier material is conducted longitudinally by reason of thepresence of the longitudinally extending bars or plates 25. In movingrlongitudinally the heavy material passes through the notches 2T. Asalready indicated, the earthy matter, such as stone, slate, etc. iscaught by the first two or three of the bars or plates .25, while themiddlings7 portion of the mixture which has some fuel value iscaught bythe remaining of said bars or plates. Both of these portions aredischarged from the lower or right-hand end of thek'jig pan.

i For the purpose of separating the earthy material such as stone,slate, sand. ete., from the middlings which contain suiiicient coal tobe `of some fuel value, I have provided an adjustable separating orswitch plate 40 which is secured at its outer or rear end to a pivotedor rotatable vertical shaft 4l which is provided with a. handle 4t2 bymeans of which it maybe rotated. The rear or pivoted end portion of theseparating plate 40 is located about the middle of the width of adischarge chute 42a. In Fig. Q of the drawings the separating or switchplate 410 is shown in a trolled middle position in consequence of whichthe material discharged from the three upper troughs formed by thelongitudinal bars or plates 25 is discharged separately from that of thematerial which is discharged from the three lowermost troughs into whichthe jig is divided by the bars or plates 25.

Endless Conveyer elevators i3 and 44 are provided for removing thematerial which is discharged from the troughs formed by the bars orplates 25. It will be understood that by adjusting the plate 4() todifferent positions, as indicated by dotted lines in Fig. 2, 'thematerial to be directed to the one conveyer or to the other may beregulated and conlf it is desired that an increased quantity orproportion of the material shall be directed to the conveyer 43 theseparating plate should be adjusted in a direction as indicated bydotted lines at 45 in Fig. 2. If, on the other hand, it is desired thata greater proportion of the material shall be directed to the elevatoror conveyer 44 the separating plate t() should be adjusted to or towardthe position shown by dotted lines at d6. rPhe position which the platell() should occupy will depend upon conditions which may be found toexist in each particular case. lf it be found that substantially all ofthe earthy mattei' is being caught within the first two of the troughsformed by the first two longitudinally extending bars or plates 25 thenthe separating plate 4:0 should be moved into position such that itsinner or forwardly extending end shall occupy a position in adjacentopposing relation to the rear end of the second of the bars or plates25. If, however, Vit is found that a large proportion of the materialwithin the fourth trough is of earthy character the separating plate l-O should be or may be adjusted in the opposite direction, so that itsswinging end shall occupy a position in adjacent opposed relation to therear end of the fourth one of the said bars or plates 25.

The coal which is discharged laterally over the upper edge of the sidewall 17 is confined within a restricted portion of the tanl; l` by meansof a longitudinally extending partition wall 50. The coal is removedfrom the bottom of the compartment formed by the wall and the side andend walls of the tanlr structure by means of an endless conveyerelevating structure shown at 51. The endless conveyer elevatingstructures 4-3, la and 5l are of usual construction, being supported attheir upper and lower ends upon sprocket wheels. The sprocket wheels atthe upper ends of the structures are mounted upon a shaft 53 upon oneend of which a spur gear 54 is mounted which is in engagement with apinion gear 55 upon a shaft 56 which is driven by means of a belt 57,which in turn is driven by means of a driving wheel 58 mounted upon theshaft 14 previously referred to.

It may happen that there is aninterruption in the supply` of the mixtureofcoal and impurities to the chute 30, which, of course, will v resultin an interruption of the supply to the jig pan. If the jig pancontinues to operate as it usually does the treatment and separa`- tionvcontinues with the result that the bottom of the jig pan becomes bare orclean. This is objectionable, because when the feed is resumed theprobabilities are that some coal will travelalong the clean bottom ofthe pan within the longitudinally extending `troughs formed by the barsor plates 25 and will be discharged with the impurities, such as stone,slate, etc. and middlings. It is desirable, therefore, that means beprovided which upon the interruption of the feed of the material to betreated will prevent the discharge of material from the rear ends ofsaid troughs.

The means or mechanism for this purpose comprises a plate 60,constituting a gate, niovably supported by means of parallel arms 61 atthe rear end of the ig structure. The outer swinging ends of these armshave pivotal connection with the plate 60. One of these arms is providedwith an extension 62 beyond its pivot to whicha connnecting rod 63 isconnected, the opposite upper end of which is connected to an arm 64which is rigidly connected with the rear end of a rotatable rod or shaft65 which is mounted in bearings upon the upper portion of the jigstructure adjacent the plane of the side wall 16 thereof. The front endof the said rotatable bar or shaft 65 extends through the chute 30adjacent one side thereof. A diaphragm 66 is mounted upon the said rodor shaft within the said chute and when no ma terial is flowing throughthe chute occupies a horizontal position. Then the diaphragm is in suchposition the gate 6() occupies closed position. The diaphragm isillustrated in the position it occupies when coal is flowing through thechute. In such position the said diaphragm occupies a substantiallyvertical plane, the plate at such time occupying an elevated openposition, as shown in Fig. 7 of theA drawings. In such position thematerial is allowed to be discharged from the rear end of the jig panstructure.

It will be understood that it is the weight of the mixture of coal,stone, slate, etc. upon the diaphragm G6 that moves the saine into theopen position, as shown in the drawing, to move the plate or gate 60also Vinto open position.

Upon interruption of the 'flow of the material to be treated through thechute the` weight of the plate or gate 60 is sutlicient to overcome theweight of the diaphragm 66, connecting rod 63, etc., whereby the saidplate or gate is allowed to inoveinto closed position. To facilitate theopening' and closing of the gate the rotatable rod or shaft is providedat its front end with a cross bar 70 )lli upon one end or the other ofwhich a weight 7l may be adjustably mounted. The said weight may bemounted upon either end of the bar as may be ne"essary, depending uponthe relative weights of the closing plate or gate and the diaphragm 66and connecting rod 63, etc. i j

It may be stated that in the operation ot the apparatus a minimumthicmess of the bed ot material upon the bottom of the jig pan lismaintained 'at all times and that the maximum thickness ot' the hed oitmaterial upon the bottom of the jig pan is equal approximately to thewidth ot the transversely extending bars or plates i It will be seenthat by my invention I have provided an apparatus of unitary structureby the employment ot' which the pure coal may be separated mosteliciently from the material, such as stone, slate, etc., and middlingswhich it is desired to eliminate, and also that the greater portion ofthe pure coal ted into the jig pan is delivered or discharged therefromas a pure j product during the initial part of the operation before ithas reached the main jigging area of the ig pan; that the bed ofmaterial upon the bottom of the jig pan is maintained in a state ofmanimum porosity due to the tact that the particles thereof are free tomove and to expand; that the material being treated may be divided intothree separate parts which thereafter' may be treated and handled as maybe desired; that the discharge of the heavier material of the mixturebeing treated is automatically interrupted upon the interruption of thefeed of material to the jig pan; and that the pulsations ofthe waterthrough the portions of the bottom of the ig pan between thelongitudinally extending bars `or plates are cqualized so to etlectseparation ot the coal from the portions of the mixture which it isdesired to eliminata Although I have described my invention aseml'iodied" in a structure for treating and cleaning coal, it will beunderstood that it may be adapted and employed for the treatment ofother substances which include por-- tions of different specificgravities which it is desired to separate.

Having thus described my invention, what l claim and desire. to secureby Letters Patent is:

l. A coal comprising a pan having :i perforated bottom and havinglongitudinally extending' spaced plates secured in adjacent relation tothe top side of said bot ioni. and also having transversely extendingspaced plates secured in spaced relation to each other adjacent the topside of said hottoin, the latter plates converging toward a centralpoint located outside of and above one end portion ot' the jig pan, thesaid latter plates being situated above the First-ninbred platest 2, Acoal jig comprising a jig pan having a perforated bottom and havinglongitudinally extending narrow plates secured in spaced relation toeach other adjacent the top side of the said bottom and also havingtransversely yextending"plates radiating from a common center andsecured in spaced relation to each other abovethe top side of the saidbottom, the said latter plates being of greater width than the formerand being providedwith notches into which the upper edge portions of thelirstnamed plates extend, the said notches forminor passagewaystransversely of and underneath thesaid second-named plates. l

A coal jig comprising a jig pan having relatively narrow platesextending longitudinally thereof in spaced relation to `each other andin adjacent relation to the top side ct' the bot-tom of said pan, andalso having transversely extending plates arranged `in spaced relationto each other above the firstnamed plates and in adjacent relation tothe bottom of the said jig pan, said transversely extending plates beingprovided with notches through which the material guided by the saidlongitudinally extending plates `may pass, and means tor separating thematerial which may be discharged from between the `tiret-named platesinto two different portions.

4. A coal comprising a jig an having a bottom and side and end wal ,thesaid bottom being exposed and the said walls extending a distance belowthe said bottom,`

and one ofthe side walls, and the end walls extending a relatively greatdistance above said bottom, and the other of said side walls extendingarelatively short distance above the said bottom, means for support-lngsald jig pan with its bottom inclined longitudinally and laterally `fromthe first-named side wall, and the saidjigpan having longitudinallyextending bars spaced from each other and mountedin adjacent relation tothe to) side of the said bottom, and also having ba de plates locatedunderneath the said bottom and in the vertical planes of the said bars,and spaced plates extending transversely of the .said bars and supportedin spaced relation to each other adjacent the top side ot the bottom ofsaid pan, saidtransversely extending plates being of greater Width thanthe said bars and being provided with notches into which the said bars`extend,` which notches provide passageways through which the impuritieswhich may be intermingled with the coal are adapted to pass.

A coal jig comprising, in combination, a jig pan inclined bothlongitudinally and transversely, a feed chute for delivering a mixtureof coal and impurities to one corner of the said jig pan, the end wallsand the side wall adjacent the said chute extending a relatively greatdistance above the bottoni of said pan while the other' side 'Wall ofsaid jig pan extends but a short distance above the bottom of said jigpan, bars or plates Secured in spaced relation to each other adjacentthe top side of the bottom of said jig pan, said bars ext-endinglongitudinally of the said pan, plates secured in spaced relation toeach other and extending transversely of said jig pan and being securedso the bottom edges thereof occupy positions adjacent the top side ofthe bottom of said jig pan, said transversely extending plates beingprovided with notches into which the said longitudinally extending barsor plates project, the first three of the said transversely f extendingbars located nearest to the said feed chutehaving their upper edgeslocated in substantially horizontal planes, while the upper edges of theremaining transversely extending plates are inclined with respect to ahorizontal plane, substantially as described.

6. A coal comprising in combination a jig pan, `means for supportingsaid jig pan with its bottom inclined both longitudinally andtransversely, whereby one edge and one end of said bottom are higherthan the oppo site edge and end respectively, a feed chute for feeding amixture of coal and impurities to said jig pan, the delivery end portionof said feed chute being located in the highest corner of the said jigpan, means for providing troughs extending longitudinally of the saidjig pan, transversely extending plates-supported in spaced relation toeach other with the bottom edges thereof adjacent the `top side of thesaid bottom, the top edges of said plates lextending a short distanceabove the top edges of the opposite sides of the said troughs, and thesaid transversely extending plates being provided with notches in theirlower edges through which material may `pass as it moves through thesaid troughs toward the discharge end of the said jig pan, the oppositeends of each of a number of said transversely extending plates near thefeed chute occupying positions snb stantially equi-distant from saidcorner whereby the upper edges thereof occupy substantially horizontalplanes, substantially as described.

7. A coal comprising a jig pan having a bottom which is inclined bothlongitudinally and transversely, means for delivering material to betreated to substantially the highest poi-nt of the said bottom, barsextending in spaced relation to each other both longitudinally andtransversely of the said bottom upon the top side thereof, thetransversely extending bars having passageways therethrough upon theundersides thereof, and means for causing water to flow transversely ofthe length of the said bottom and substantially in the direction of thelength of the Vsaid transverse bars, substantially as described.

8. In coal washing apparatus comprising a tank containing water, thecombination of a jig pan located in the said water the said jig panhaving a bottom provided with perforations and also having spacednarrowl bars secured therein in adjoining relation to the top side ofthe said bottom and extending longitudinally thereof and also havingplates secured within the said pan in adjoining relation to the top sideof the `said bottom, which plates extend diagonally of the length of thesaid jig pan and being provided with notches located within the spacesbetween the said bars and forming passageways, means for e'ectingvibration of the said pan, and plates mounted upon the under side of thebottom of the jig pan in vertical planes for directing independentstreams of water upwardly through the perforations in the bottom of thesaid jig pan between the said bars which streams are caused by thevibration of the said pan.

In testimony that l claim the foregoing as my invention, I have hereuntosigned my name this 11th day of May, A. D., 1925.

MAXIMLIAN S. HAGHITA.

